Method and apparatus for detecting imminent use of an electronic device

Abstract

An apparatus and method for determining imminent use of an electronic device. An infrared sensor is used to determine when a human hand is approaching the electronic device and breaches an activation distance. The infrared sensor is partially covered by a mask having a mask opening formed therethrough so that only a portion of ambient light reaches the infrared sensor. When the infrared sensor comprises two or more sensing elements, each sensing element is completely masked while one sensing element is partially masked, thereby allowing only one sensing element to receive ambient light. Signals from the infrared sensor are processed to determine when a human hand is approaching the electronic device and breaches the activation distance. When detected, the electronic device self-illuminates in order to make it easier for a person to interact with the electronic device.

We claim: 
     
         1 . An electronic device, comprising:
 a infrared sensor for detecting a change of infrared energy within an activation distance from the electronic device, the activation distance comprising a distance where a user's hand is detected as it approaches the electronic device;   a processor coupled to the infrared sensor, for receiving an electronic signal from the infrared sensor indicative of the change of infrared energy, for determining that the electronic signal comprises an indication of imminent use of the electronic device, and for activating an illumination device in response thereto; and   the illumination device, coupled to the processor, for illuminating the electronic device when the processor has determined imminent use of the electronic device.   
     
     
         2 . The electronic device of  claim 1 , wherein the activation distance is less than 18 inches. 
     
     
         3 . The electronic device of  claim 1 , further comprising:
 a mask mounted over the infrared sensor, the mask comprising a mask opening for limiting an amount of ambient light that reaches the infrared sensor.   
     
     
         4 . The electronic device of  claim 3 , wherein a size of the mask opening is proportional to the activation distance. 
     
     
         5 . The electronic device of  claim 3 , wherein an area of the mask opening and an area of a sensing element of the infrared sensor defines the activation distance. 
     
     
         6 . The electronic device of  claim 3 , wherein the infrared sensor comprises two or more sensing elements, wherein the mask completely covers all but a first sensing element of the two or more sensing elements and partially covers the first sensing element via the mask opening. 
     
     
         7 . The electronic device of  claim 1 , further comprising:
 a housing that encloses the infrared sensor and the processor, the housing comprising a housing opening in substantial alignment with the infrared sensor for allowing ambient light to fall onto the infrared sensor.   
     
     
         8 . The electronic device of  claim 7 , wherein the infrared sensor comprises a sensing element, wherein the housing opening is smaller than an area of the sensing element. 
     
     
         9 . The electronic device of  claim 8 , wherein the infrared sensor comprises two or more sensing elements, wherein the housing aperture is positioned over a first of the two or more sensing element only. 
     
     
         10 . The electronic device of  claim 9 , wherein the two or more sensing elements are substantially flush against an inner surface of the housing. 
     
     
         11 . The electronic device of  claim 7 , further comprising:
 a lens deposited into the housing opening comprising a material with a high infrared transmissibility rating and a low visible light transmissibility rating.   
     
     
         12 . The electronic device of  claim 1 , further comprising:
 electronic circuitry coupled to the processor to internally filter and amplify an internal electrical signal generated by the passive infrared sensor in response to the increase in infrared energy.   wherein the infrared sensor comprises a passive, pyroelectric sensor   
     
     
         13 . The electronic device of  claim 1 , wherein the infrared sensor comprises one or more passive infrared sensing elements and active electrical components, the active electrical components for processing signals produced by a first one of the passive infrared sensing elements, for determining when infrared energy sensed by the first passive infrared sensing element indicates imminent use of the electronic device, for generating an interrupt signal when imminent use of the electronic device is determined, and for providing the interrupt to the processor that indicates imminent use of the electronic device. 
     
     
         14 . A method for determining imminent use of an electronic device using a digital infrared sensor, comprising:
 limiting an amount of ambient light that falls on the infrared sensor with a mask, the mask comprising a mask opening that allows some ambient light to fall on a first sensing element of the infrared sensor, the mask opening sized to define an activation distance in front of the electronic device that, when breached by a human hand, causes an electronic signal to be generated by the infrared sensor;   receiving the electronic signal by the processor; and   in response to receiving the electronic signal, causing one or more illumination devices to illuminate the electronic device.   
     
     
         15 . A method for determining imminent use of an electronic device using a passive pyroelectric sensor, comprising:
 limiting an amount of ambient light that falls on the passive pyroelectric sensor with a mask, the mask comprising a mask opening that allows some ambient light to fall on the passive pyroelectric sensor, the mask opening sized to define an activation distance in front of the electronic device that, when breached by a human hand, causes the electronic device to become illuminated;   generating an electric signal by the passive pyroelectric sensor in response to detecting a change in infrared energy;   amplifying the electric signal to form an amplified signal;   filtering the amplified electric signal to create a filtered signal;   comparing the filtered signal to a threshold;   determining that a human hand has breached the activation distance when the filtered signal exceeds the threshold; and   in response to determining that the human hand has breached the activation distance, causing one or more illumination devices located on or within the electronic device to illuminate the electronic device.